24 resultados para Synthetic traffic generation

em Helda - Digital Repository of University of Helsinki


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This research is about jazz in Chile in relation to modernity and identity. Final chapters focus and detach latest jazz musician s generation in 1990 decade and composer guitarist Angel Parra. An historic and sociological approach is developed, which will be useful for modernity and identity analysis, and so on post modernity and globalization. Modernity has been studied in texts of Adorno, Baudrillard, Brünner, García Canclini, Habermas and Jameson. Identity has been studied in texts of Aharonián, Cordúa, Garretón, Gissi, Larraín and others. Chapter 3 is about Latin-American musicology and jazz investigations, in relation to approach developed in chapter 2. Chapters 4 and 5 are about history of jazz in Chile until beginning of XXI century. Chapter 6 focuses in Ángel Parra Orrego. Conclusions of this investigation detach the modernist mechanical that has conducted jazz development in Chile, which in Ángel Parra´s case has been overcame by a post modernist behaviour. This behaviour has solved in a creative way, subjects like modernity and identity in jazz practice in a Latin-American country.

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Road traffic accidents are a large problem everywhere in the world. However, regional differences in traffic safety between countries are considerable. For example, traffic safety records are much worse in Southern Europe and the Middle East than in Northern and Western Europe. Despite the large regional differences in traffic safety, factors contributing to different accident risk figures in different countries and regions have remained largely unstudied. The general aim of this study was to investigate regional differences in traffic safety between Southern European/Middle Eastern (i.e., Greece, Iran, Turkey) and Northern/Western European (i.e., Finland, Great Britain, The Netherlands) countries and to identify factors related to these differences. We conducted seven sub-studies in which I applied a traffic culture framework, including a multi-level approach, to traffic safety. We used aggregated level data (national statistics), surveys among drivers, and data on traffic accidents and fatalities in the analyses. In the first study, we investigated the influence of macro level factors (i.e., economic, societal, and cultural) on traffic safety across countries. The results showed that a high GNP per capita and conservatism correlated with a low number of traffic fatalities, whereas a high degree of uncertainty avoidance, neuroticism, and egalitarianism correlated with a high number of traffic fatalities. In the second, third, and fourth studies, we examined whether the conceptualisation of road user characteristics (i.e., driver behaviour and performance) varied across traffic cultures and how these factors determined overall safety, and the differences between countries in traffic safety. The results showed that the factorial agreement for driver behaviour (i.e., aggressive driving) and performance (i.e., safety skills) was unsatisfactory in Greece, Iran, and Turkey, where the lack of social tolerance and interpersonal aggressive violations seem to be important characteristics of driving. In addition, we found that driver behaviour (i.e., aggressive violations and errors) mediated the relationship between culture/country and accidents. Besides, drivers from "dangerous" Southern European countries and Iran scored higher on aggressive violations and errors than did drivers from "safe" Northern European countries. However, "speeding" appeared to be a "pan-cultural" problem in traffic. Similarly, aggressive driving seems largely depend on road users' interactions and drivers' interpretation (i.e., cognitive biases) of the behaviour of others in every country involved in the study. Moreover, in all countries, a risky general driving style was mostly related to being young and male. The results of the fifth and sixth studies showed that among young Turkish drivers, gender stereotypes (i.e., masculinity and femininity) greatly influence driver behaviour and performance. Feminine drivers were safety-oriented whereas masculine drivers were skill-oriented and risky drivers. Since everyday driving tasks involve not only erroneous (i.e., risky or dangerous driving) or correct performance (i.e., normal habitual driving), but also "positive" driver behaviours, we developed a reliable scale for measuring "positive" driver behaviours among Turkish drivers in the seventh study. Consequently, I revised Reason's model [Reason, J. T., 1990. Human error. Cambridge University Press: New York] of aberrant driver behaviour to represent a general driving style, including all possible intentional behaviours in traffic while evaluating the differences between countries in traffic safety. The results emphasise the importance of economic, societal and cultural factors, general driving style and skills, which are related to exposure, cognitive biases as well as age, sex, and gender, in differences between countries in traffic safety.

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This study examines supervisors' emerging new role in a technical customer service and home customers division of a large Finnish telecommunications corporation. Data of the study comes from a second-generation knowledge management project, an intervention research, which was conducted for supervisors of the division. The study exemplifies how supervision work is transforming in high technology organization characterized with high speed of change in technologies, products, and in grass root work practices. The intervention research was conducted in the division during spring 2000. Primary analyzed data consists of six two-hour videorecorded intervention sessions. Unit of analysis has been collective learningactions. Researcher has first written conversation transcripts out of the video-recorded meetings and then analyzed this qualitative data using analytical schema based on collective learning actions. Supervisors' role is conceptualized as an actor of a collective and dynamic activity system, based on the ideas from cultural historical activity theory. On knowledge management researcher has takena second-generation knowledge management viewpoint, following ideas fromcultural historical activity theory and developmental work research. Second-generation knowledge management considers knowledge embedded and constructed in collective practices, such as innovation networks or communities of practice (supervisors' work community), which have the capacity to create new knowledge. Analysis and illustration of supervisors' emerging new role is conceptualized in this framework using methodological ideas derived from activity theory and developmental work research. Major findings of the study show that supervisors' emerging new role in a high technology telecommunication organization characterized with high speed of discontinuous change in technologies, products, and in grass-root practices cannot be defined or characterized using a normative management role/model. Their role is expanding two-dimensionally, (1) socially and (2) in new knowledge, and work practices. The expansion in organization and inter-organizational network (social expansion) causes pressures to manage a network of co-operation partners and subordinates. On the other hand, the faster speed of change in technological solutions, new products, and novel customer wants (expansion in knowledge) causes pressures for supervisors to innovate quickly new work practices to manage this change. Keywords: Activity theory, knowledge management, developmental work research, supervisors, high technology organizations, telecommunication organizations, second-generation knowledge management, competence laboratory, intervention research, learning actions.

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Rural income diversification has been found to be rather the norm than the exception in developing countries. Smallholder households tend to diversify their income sources because of the need to manage risks, secure a smooth flow of income, allocate surplus labour, respond to various kinds of market failures, and apply coping strategies. The Agricultural Household Model provides a theoretical rationale for income diversification in that rural households aim at maximising their utility. There are several elements involved, such as agricultural production for their own consumption and markets, leisure activities and income from non-farm sources. The aim of the present study is to enhance understanding of the processes of rural income generation and diversification in eastern Zambia. Specifically, it explores the relationship between household characteristics, asset endowments and income-generation patterns. According to the sustainable- rural-livelihoods framework, the assets a household possesses shape its capacity to seize new economic opportunities. The study is based on two surveys conducted among rural smallholder households in four districts of Eastern Province in Zambia in 1985/86 and 2003. Sixty-seven of the interviewed households were present in both surveys and this panel allows comparison between the two points of time. The initial descriptive analysis is complemented with an econometric analysis of the relationships between household assets and income sources. The results show that, on average, 30 per cent of the households income originated from sources outside their own agriculture. There was a slight increase in the proportion of non-farm income from 1985/86 to 2003, but total income clearly declined mainly on account of diminishing crop income. The land area the household was able to cultivate, which is often dependent on the available labour, was the most significant factor affecting both the household-income level and the diversification patterns. Diversification was, in most cases, a coping strategy rather than a voluntary choice. Measured as income/capita/day, all households were below the poverty line in 2003. The agricultural reforms in Zambia, combined with other trends such as changes in rainfall pattern, the worsening livestock situation and the incidence of human disease, had a negative impact on agricultural productivity and income between 1985/86 and 2003. Sources of non-farm income were closely linked to agriculture either upstream or downstream and the income they generated was not enough to compensate for the decline of agricultural income. Household assets and characteristics had a smaller impact on diversification patterns than expected, which could reflect the lack of opportunities in the remote rural environment.

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Even though cellulose is the most abundant polymer on Earth, its utilisation has some limitations regarding its efficient use in the production of bio-based materials. It is quite clear from statistics that only a relatively small fraction of cellulose is used for the production of commodity materials and chemicals. This fact was the driving force in our research into understanding, designing, synthesising and finding new alternative applications for this well-known but underused biomaterial. This thesis focuses on the developing advanced materials and products from cellulose by using novel approaches. The aim of this study was to investigate and explore the versatility of cellulose as a starting material for the synthesis of cellulose-based materials, to introduce new synthetic methods for cellulose modification, and to widen the already existing synthetic approaches. Due to the insolubility of cellulose in organic solvents and in water, ionic liquids were applied extensively as the reaction media in the modification reactions. Cellulose derivatives were designed and fine-tuned to obtain desired properties. This was done by altering the inherent hydrogen bond network by introducing different substituents. These substituents either prevented spontaneous formation of hydrogen bonding completely or created new interactions between the cellulose chains. This enabled spontaneous self-assembly leading to supramolecular structures. It was also demonstrated that the material properties of cellulose can be modified even those molecules with a low degree of substitution when highly hydrophobic films and aerogels were prepared from fatty acid derivatives of nanocellulose. Development towards advanced cellulose-based materials was demostrated by synthesising chlorophyllcellulose derivatives that showed potential in photocurrent generation systems. In addition, liquid crystalline cellulose derivatives prepared in this study, showed to function as UV-absorbers in paper.

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Wireless access is expected to play a crucial role in the future of the Internet. The demands of the wireless environment are not always compatible with the assumptions that were made on the era of the wired links. At the same time, new services that take advantage of the advances in many areas of technology are invented. These services include delivery of mass media like television and radio, Internet phone calls, and video conferencing. The network must be able to deliver these services with acceptable performance and quality to the end user. This thesis presents an experimental study to measure the performance of bulk data TCP transfers, streaming audio flows, and HTTP transfers which compete the limited bandwidth of the GPRS/UMTS-like wireless link. The wireless link characteristics are modeled with a wireless network emulator. We analyze how different competing workload types behave with regular TPC and how the active queue management, the Differentiated services (DiffServ), and a combination of TCP enhancements affect the performance and the quality of service. We test on four link types including an error-free link and the links with different Automatic Repeat reQuest (ARQ) persistency. The analysis consists of comparing the resulting performance in different configurations based on defined metrics. We observed that DiffServ and Random Early Detection (RED) with Explicit Congestion Notification (ECN) are useful, and in some conditions necessary, for quality of service and fairness because a long queuing delay and congestion related packet losses cause problems without DiffServ and RED. However, we observed situations, where there is still room for significant improvements if the link-level is aware of the quality of service. Only very error-prone link diminishes the benefits to nil. The combination of TCP enhancements improves performance. These include initial window of four, Control Block Interdependence (CBI) and Forward RTO recovery (F-RTO). The initial window of four helps a later starting TCP flow to start faster but generates congestion under some conditions. CBI prevents slow-start overshoot and balances slow start in the presence of error drops, and F-RTO reduces unnecessary retransmissions successfully.

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The cation-Cl- cotransporter (CCC) family comprises of Na+-Cl- cotransporter (NCC), Na+-K+-2Cl- cotransporters (NKCC1-2), and four K+-Cl- cotransporters (KCC1-4). These proteins are involved in several physiological activities, such as cell volume regulation. In neuronal tissues, NKCC1 and KCC2 are important in determining the intracellular Cl- levels and hence the neuronal responses to inhibitory neurotransmitters GABA and glycine. One aim of the work was to elucidate the roles for CCC isoforms in the control of nervous system development. KCC2 mRNA was shown to be developmentally up-regulated and follow neuronal maturation, whereas NKCC1 and KCC4 transcripts were highly expressed in the proliferative zones of subcortical regions. KCC1 and KCC3 mRNA displayed low expression throughout the embryogenesis. These expression profiles suggest a role for CCC isoforms in maturation of synaptic responses and in the regulation of neuronal proliferation during embryogenesis. The major aim of this work was to study the biological consequences of KCC2-deficiency in the adult CNS, by generating transgenic mice retaining 15-20% of normal KCC2 levels. In addition, by using these mice as a tool for in vivo pharmacological analysis, we investigated the requirements for KCC2 in tonic versus phasic GABAA receptor-mediated inhibition. KCC2-deficient mice displayed normal reproduction and life span, but showed several behavioral abnormalities, including increased anxiety-like behavior, impaired performance in water maze, alterations in nociceptive processing, and increased seizure susceptibility. In contrast, the mice displayed apparently normal spontaneous locomotor activity and motor coordination. Pharmacological analysis of KCC2-deficient mice revealed reduced sensititivity to diazepam, but normal gaboxadol-induced sedation, neurosteroid hypnosis and alcohol-induced motor impairment. Electrophysiological recordings from CA1-CA3 subregions of the hippocampus showed that KCC2 deficiency affected the reversal potentials of both the phasic and tonic GABA currents, and that the tonic conductance was not affected. The results suggest that requirement for KCC2 in GABAergic neurotransmission may differ among several functional systems in the CNS, which is possibly due to the more critical role of KCC2 activity in phasic compared to tonic GABAergic inhibition.